Certain surgical procedures require the surgeon to perform delicate operations on tissues within the body that are moving or otherwise unstable. The ability to stabilize or immobilize the surgical site provides greatly improved surgical accuracy and precision and reduces the time required to complete a particular procedure. A large and growing number of surgeons, for example, are routinely performing successful coronary artery bypass graft (CABG) surgery on the beating heart by temporarily stabilizing or immobilizing a localized area of the beating heart. Methods and apparatus for performing a CABG procedure on the beating heart are described in U.S. Pat. Nos. 5,894,843 and 5,727,569 to Benetti et al., the entirety of which is herein incorporated by reference.
In a typical CABG procedure, a blocked or restricted section of coronary artery, which normally supplies blood to some portion of the heart, is bypassed using a source vessel or a graft vessel to re-establish blood flow to the artery downstream of the blockage. This procedure requires the surgeon to create a fluid connection, or anastomosis, between the source or graft vessel and an arteriotomy or incision in the coronary artery. Forming an anastomosis between two vessels in this manner is a particularly delicate procedure requiring the precise placement of tiny sutures in the tissue surrounding the arteriotomy in the coronary artery and the source or graft vessel.
The rigors of creating a surgical anastomosis between a coronary artery and a graft or source vessel demands that the target site for the anastomosis be substantially motionless. To this end, a number of devices have been developed which are directed to stabilizing a target site on the beating heart for the purpose of completing a cardiac surgical procedure, such as completing an anastomosis. Representative devices useful for stabilizing a beating heart are described, for example, in U.S. Pat. Nos. 5,894,843; 5,727,569; 5,836,311; and 5,865,730.
As beating heart procedures have evolved, new challenges have arisen in the design and engineering of the stabilization devices. The heart is typically accessed by way of a surgical incision such as a sternotomy or thoracotomy. Often one or more of the blocked or restricted coronary arteries are located a good distance away from the access incision requiring the stabilization device to traverse a longer and more tortuous path and engage the surface of the heart at somewhat difficult angular relationships or orientations. Under the most severe conditions, devices which operate to provide a mechanical compression force to stabilize the beating heart encounter difficulty maintaining mechanical traction against the surface of the heart. Similarly, devices which utilize vacuum to engage the heart have a great deal of difficulty creating and maintaining an effective seal against the moving surface of the heart.
Even when the beating heart has been effectively stabilized, the target coronary artery may be obscured by layers of fat or other tissue and is very difficult for the surgeon to see. Moreover, the stabilization devices may distort the tissue surrounding the coronary artery or the coronary artery itself such that the arteriotomy is maintained in an unfavorable presentation for completion of the anastomosis. For example, the coronary artery in the area of the arteriotomy may become excessively flattened, compressed or stretched in a manner that impedes the placement of sutures around the perimeter of the arteriotomy.
In view of the foregoing, it would be desirable to have methods and devices for stabilizing the beating heart that are capable of maintaining atraumatic engagement with the surface of the beating heart over a wider range of conditions and orientations. It would be further desirable to have stabilization methods and devices which provide for favorable presentation of the coronary artery.